Means for gripping rods



Nov. 28, 1961 J. M. J. ANNEGARN 3,010,568

MEANS FOR GRIPPING RODS Filed July 28, 1960 2 Sheets-Sheet 1 Inn/Em 1951 J. M. J. ANNEGARN 3,0

MEANS FOR GRIPPING RODS Filed July 28, 1960 2 Sheets-Sheet 2 FIG. 3

I 5, (12m, 64, ,ZM a d/Z5 Ayala 75 United Smtes Patent F 3,010,568 MEANS FOR GRIPPING RODS Joseph M. J. Annegarn, 37 Sunnyside Ave., Benoni, Union of South Alrica Filed July 28, 1960, Ser..N0. 45,836 Claims priority, application Union of South Africa Aug. 7, 1959 8 Claims. (Cl. 205-24) This invention relates to means for gripping rods during working thereof and more particularly to .a means which will effectively hold the rods without marking them.

During working of rods particularly when cold drawing shafting from hot rolled stock it is advantageous to draw the stock through the die without marking or otherwise damaging that portion of the shafting which is gripped. Since the load on the shar'ting during such an operation frequently reaches up to sixty per centum of the tensile strength of the rod it will be appreciated that a powerful grip must be applied to the rod.

It is the object of this invention to provide a means for ceding rod under circumstances such as those above referred to which will afford the necessary grip Without damage and also to enable rod to be fed continuously.

According to this invention there is provided a means for gripping rod comprising a segmented clamping member adapted to surround the rod, said clamping member enveloped in a resilient sheath and assembled in a rigid sleeve and means for applying fluid pressure between the cylinder arrangement fed through'a valve and for two such assemblies to be arranged in tandem.

A further feature of this invention provides for the clamping member to be in the form of a metal cylinder having an axial bore therein and equi-angular radial slots through the cylinder wall extending alternately from each end of the cylinder for the majority of the length of the latter.

A preferred form of this invention as applied to the cold drawing of shaiting is illustrated in the accompanying drawings in which:

FIGS. 1 and 2 are schematic layouts of the general assembly and hydraulic network respectively,

FIG. 3 is a part sectional view of one'piston andcylinder assembly, and

FIG. 4 is an oblique view of a clamping member.

In this embodiment two hydraulic piston and cylinder assemblies 1, 2 are mounted in tandem axially in line with the die 3 through which hot rolled rod 4 is to be drawn into shafting 5. Both piston and cylinder assemblies 1, 2 are identical and as shown in FIG. 3 the piston 6 has a hollow piston rod 7 extending through the normal type of seals 8 at either end of the cylinder 9.

Each piston rod 7 forms a sleeve 10 for at least one segmented clamping member 11 which will preferably be, as shown in FIG. 4 in the form of a steel clamping cylinder axially bored slightly larger than the size of shafting to be drawn. It will be appreciated that other metals and even suitable plastic materials may be used for the clamping members. Radial slots 12, 13 are made through the wall of the clamping cylinder 11 and spaced equi-angularly apart with the slots 12, 13 extending alternately from each end of said cylinder for the majority of its length.

Each clamping cylinder 11 is enveloped in a resilientsheath 14 (FIGURE 3) of suitable plastic material such as high density polyethylene or material having similar properties and the sheathed cylinder is retained in the 3,910,553 Patented Nov. 28, 1961 sleeve by end plugs 15. Seals 16 are positioned around the sheaths 14 and passageways 15a made so that fluid medium, preferably oil, may be introduced under pressure between the sleeve 10 and the sheath 14, through a high pressure flexible lead 17.

The hydraulic piston and cylinder assemblies 1 and 2 in FIGURE 1 are made double acting and fed for forward movement through independent sequence valves 18, 19 (FIGURE 2). Independent pumps 21, 22 are provided for each of the assemblies 1, 2 and a quick return motion is provided by having a differential efifecting piston area for forward and return strokes of the pistons 6. This is most easily effected by having the sizes of the piston rods 7 on each side of the pistons 6 different with the larger rods on the return stroke side of the pistons 6. This quick return motion ensures smooth take over rom one assembly to the other as will be described below.

Each sequence valve 18 or 19 is adjusted to ensure a supply pressurised fluid between the sheath 14 and sleeve 10 as above described and, when a predetermined pressure is reached, to feed behind the relative piston (FIG- URE 3). The tandem arrangement of the assemblies 1 and 2 enables a continuous pull to be efiected on the hot rolled rod 4 drawn through the die 3, to form shafting 5. From the second assembly 2 the shafting is passed through a standard straightening mechanism 20 and may then be cut in the desired lengths.

In use a short length of pro-made shaftiug is butt welded at one end to a coil of hot rolled rod 4. The free end of the shafiting is fed through the die 3 and clamping members 11 formed in the piston rods 7 of the piston andcylindcr assemblies 1, 2 and through the straightening mechanism 20.

At the instant depicted in FIG. 1 the assembly 2 is about to draw the rod 4 through the die 3 while the piston in assembly 1 is about to start its return stroke.

The control valves 23, 24 (FIGURE 2) for each cylinder are adapted to be reversed by the relative positions of the pistons in such a way that'as the piston of assembly 1 nears the end of its working stroke it reverses the position of the control valve 24 for assembly 2 which then, through its sequence valve 19, commences its working stroke. As pressureis applied to the assembly 2. it first causes contracting of the segmented clam-ping cylinder or cylinders 11 onto the shaft 5 and then draws the shaft '5 and rod 4 attached thereto through the die 3. The force of the grip may be predetermined through the sequence valve 19 and the clamping cylinders 11 are made sufficiently long to ensure no damage is done tothe surface of the shafting during the drawing operation. Preferably the grip. of the. clamping member will be calculated so as to be in the correct proportion to the effective piston area. The clamping members 11 will also preferably be made in separate sections so that any curvature of the shalting 5- drawn through the die 3 will be compensated for to a large degree over the length gripped by the clamping members;

Shortly after the piston of assembly 1 has brought assembly 2 in working operation it reverses its own control valve 23 thus immediately releasing the pressure causing contraction of its clamping cylinders and reversing the direction of piston travel. Due tothe quick return of the piston as mentioned above the assembly 1 reaches the starting point of the working stroke before assembly 2 has completed its working stroke and there is a short dwell for assembly 1 until the cycle above described is.

started again but controlled through the position of the piston of assembly 2. H

The actual operation of the control valves 23, 24 is preferably powered from an external source, conveniently air pressure, and stops on the piston rods of the assemblies 1, 2 operate pilot valves or similar mechanisms in the external power source.

During the dwell after each return stroke of the pistons the oil is pumped back to the reservoir 25 through any convenient mechanism such as the relief valves 26, 27 as shown in FIG. 2.

Master and slave piston and cylinder assemblies may also be used with a closed circuit utilized for the return of the inoperative assembly. In this case quick return motion will not be possible and a vent valve should be provided to prevent over-travel of the slave piston.

A hydraulically operated guillotine will preferably be provided beyond the straightening mechanism and-this guillotine will be operated through a trip mechanism controlled by the shafting coming out of the straightening mechanism. Accurate lengths of shafting may thus be severed from the production and the operation of the tripping mechanism will momentarily release the piston and cylinder assemblies from the hydraulic pressure while the guillotine is operated by part of the volume of the hydraulic system.

Using the tandem arrangement as above described enables rod to be continuously and fully automatically drawn in shafting by butt welding continuous lengths or coils of the hot rolled rod to each other with consequent increase in speed and efliciency.

In an alternative arrangement the sleeve and sheath assembly may form an extension to one or both ends of the piston rods.

' It will beappreciated that the gripping means described in this specification may be used in other applications than the preferred embodiment set out above and it will be understood that the gripping means may be draulic pressure and a sequence valve for each piston and cylinder assembly positioned to control the flow of fluid alternately to each side of each piston and cylinder assembly.

4. A means as defined in claim 2 wherein each piston and cylinder assembly is double acting.

5. A means for pulling rods comprising a pair of double acting piston and cylinder assemblies arranged in tandem, a diflerential effective piston area on the sides of each' piston, a pair of rigid sleeves forming hollow piston rods to the pistons, and in which there is in each sleeve a resilient sheath assembled within said sleeve,

seals between each sleeve and the ends of each sheath,

utilized to push material through a die or the like and is not limited to the drawing arrangement described.

What I claim as new and desireto' secure by Letters Patent is: p

l. A means for pulling rods comprising a hydraulic piston and cylinder assembly, a rigid sleeve forming a hollow piston rod to the piston, a resilient sheath assembled within said sleeve, seals between the'sleeve and ends of the sheath, a segmented clamping member located within said sheath and means for applying fluid pressure between the sheath. and the sleeveL 2. A means for, pulling rods comprising a pair of hydraulic piston and cylinder assemblies arrauged'in tandem, a pair of rigid sleeves forming hollow piston rods to the pistons and in which there is in each sleeve a resilient sheath assembled within said sleeve, seals between each sleeve and the ends of each sheath, a segmented clamping member located within each'f sheath and means for applying fluid pressure between each sheath and sleeve combination. 7

' 3. A means as defined in claim 2 wherein the means for applying hydraulic pressure includes a source of hya segmented clamping member located within each sheath and means for applying fluid pressure between each sheath and sleeve combination.

6. A means-as defined in claim 5 wherein each clamping member is a metal cylinder having an axial bore therein and equi-angularly spaced radial slots through the cylinder wall extending alternately from each end of the cylinder for the majority of the length of said cylinder. 7 7. A means for cold reducing metal rods into shafting comprising a pair of double acting piston and cylinder assemblies arranged in tandem, a diflerential eflective piston area on the sideof each piston, each piston rod being hollow and forming a rigid sleeve, a resilient sheath assembled within each sleeve, seals between each sleeve and the ends of each sheath, a clamping member in the form of a metal cylinder having an axial bore therein and equi-angularly spaced radial slots through the Wall of said clamping member extending alternatively from each end of said clamping member for the majority of the length of said clamping member arranged within each sheath, a source of hydraulic pressure and a sequence valve for each piston and cylinder assembly for controlling the flow of fluid alternately to each side of the piston in each piston and cylinder assembly, and a fixed reducing die associated with the pair of piston and cylinder assemblies.

- 8. A means as defined in claim 7 inwhich each clamping member consists of a plurality of metal cylinders each having an axialbore therein and equi-angularly spaced radial slots through the wall of said clamping member extending alternately from each end of said clamping member for the majority of the length of said clamping member.

References Cited in the file of this patent UNITED STATES PATENTS Bentley et a1 Apr. 15, 1958 

